Relay selecting-circuit for artificial lines.



C. S. DEMAREST. RELAY SELECHNG cmcufi FOR ARTiFICIAL LINES.

APPUCATION FILED JUNE I5, I91?- Patent'ed July 23, 1918.

m VIENTOR ATTORNEY repeater, said relay being under the control of any one of the lines of the corresponding group of transmission lines.

With this general description in mind, the invention will now be fully understood from a description of the operation. As suming that it is desired to connect line L to line L, through the cord circuit repeater R, the plug P is inserted in the jack J 1 and the plug P isinserted in the jack J A circuit is thereby completed ov r the sleeve contacts of plug P and jack J,, from battery through the winding of relay 1, sleeve contacts of the plug and jack, and winding of relay 2 to ground. Relays 1 and 2 are energized over this circuit, relay 2 momentarily closing a circuit from ground over its makebreak contacts, over the lower back contact and through the winding of relay 3 and over the front contact of relay 1 to battery. As soon as the armature of relay 2 is fully pulled up, the make-break contact is opened and the circuit "just traced is broken but the contact remains closed a sutlicicnt length of time before this occurs to energize the relay 3 over this circuit. Relay 3 upon being energize-d completes a locking circuit from battery over the front contact of relay 1, winding and front contact 01 relay 3 and through the winding of relay 4t to ground. Relay 4 is energized over this circuit and disconnects the artificial line N from the repeater R. The relay 3 is locked up over the circuit just traced and at its upper contacts connects the artificial line N, to the repeater.

Returning now to the calling end of the repeater, upon inserting the plug P into the jack J, a circuit is closed from battery through the winding of relay 5, sleeve contacts of plug P and jack J and Winding of relay 6 to ground. Relays 5 and 6 are energized over this circuit, relay (3 at its make-break contact closing a momentary circuit from ground over the make-break contacts. of relay 6, lower back contact and Winding of relay 7, from contact of relay 5 to battery. When the armature of relay 6 is fully pulled up this circuit is broken but thecircuit is completed for a sufiicient length or" time to permit of the energization of relay 7. Relay 7, upon being energized, at its lower front contact closes a locking circuit from battery, front contact of relay 5, Winding and lower front contact of relay 7 and the winding of relay 8 to ground. Relay 8 is thereby energized and disconnects the artificial line N from the calling end of repeater R, while relay 7 at its upper contacts connects the artificial line N thereto.

It will now be seen that the lines L and L, are interconnected through the repeater and are balanced by artificial lines N and N Had the connection been established between the lines L, and L relays 9 and 1G would have been energized to complete momentary circuits through the windings of relays 3 and 7 whereby said relays would have been operated to connect the artificial lines N 1 and N to the repeater in the manner just described. It will be noted that the make-break contacts of the relays individual to lines of the same group are connected in pa allel to a conductor leading to the connecting relays which operate to connect an artificial line to the repeater.

In the $2156 of the lines of the two groups to which lines L, and L, belong, the relays individual to the line do not control any selecting circuit. Therefore, if the connection be made between lines L, and L, or between lines L, and L, through the repeater R, although relays 11 and 12 are energized, no circuits are completed thereby and consequently the relays L and 8 are not energized so that artificial lines N and N, will remain connected to the answering and calling ends of the repeater respectively, to balance the lines L, and L In practice it may be found that some one group of lines is much larger than any other group and it will be, therefore, advantageous to design the artificial lines l and N which are normally connectcd to the repeater, in such a manner as to balance the lines belonging to such large group. If this is done, in a large number of connections no artificial line need be selected, as the proper artificial line will be already associated with the repeater. However, when the rcpeater is associated with a line in a smaller group, an artificial line 100 will be selected and connected to the repeater, the artificial line normally connected thereto being at the same time disconnected.

By means of the arrangements abovdifi; scribed, it will be seen that simple and eili- 105 cient means for the automatic selection of an artificial line to balance a transmission line has been provided, and while the invention has been disclosed as embodied in certain forms which are considered desirable, it will 110 be understood that it may be embodied in many widely different organizations with out departing from the spirit of the appended claims.

What is claimed is:

1. A plurality of transmission lines, a repeater for interconnecting said lines, a plurality of artificial lines associated with said repeater, one of said artificial lines being normally connected to said repeater, and 120 means operating in response to the connection of said repeater to a transmission line to disconnect said artificial line and connect another artificial line to the repeater.

2. A plurality of transmission lines di- 125 vided into groups, a repeater for interconnecting said lines, artificial lines associated with said repeater and corresponding to the various groups of transmission lines, the artificial line corresponding to one group be 130 and disconnection of the art] to a the repeater.

ing normally connected to the repeater so as to balance any line of that group when the repeater is associated therewith, and means responsive to the connection of the repeater to a line of another group to disconnect the normally connected artificial line from the repeater, and to connect an artificial line corresponding to said other group 3 A plurality of transmission lines divided into groups, a repeater for interconnecting said lines, artificial lines associated with the repeater and corresponding to the various groups of transmission lines, the artificial line corresponding to one group being normally connected to the repeater so as to balance any line of that group when the repeater is associated therewith, and selecting relays responsive to the connection of the repeater to a line of another group to disconnect the normally connected artificial line from the repeater and to connect an artificial line corresponding to said other group to the repeater.

4. A plurality of transmission lines, a repeater for interconnecting said lines, a pluvrality of balancing artificial lines associated with the repeater, one of said artificial lines being normally connected to the repeater, and relays corresponding to each of said artificial lines and controllin the connection %cial lines from the repeater, said relays being unresponsive to the association of the repeater with certain lines so that the normally connected artificial line remains associated with the repeater, and certain of said relays being responsive to the association of the repeater with other lines to disconnect the normally connected artificial line and connect another artificial line to the repeater.

5. A telephone repeater, a plurality of artificial lines associated therewith, a relay normally connecting one of said artificial lines to the repeater, relays controlling the connection of each of the other artificial lines to the repeater, and means whereby when any one of the latter relays operates to connect an artificial line to the repeater said first relay operates to disconnect the corresponding artificial line from the re eater.

6. A plurality of transmission ines divided into groups, a repeater for interconnecting said lines, a plurality of artificial lines for said'repeater, one of said lines being preselected to balance any line of one group when the repeater is associated therewith, and means to select another artificial line wheirthe repeater is associated with a line in another group.

In testimony whereof, I have signed my nameto" this specification this seventh day of J1ine 1917.

. CHARLES S. DEMAREST; 

